#include <iostream>
using namespace std;

class _test {
public:
	_test() {
		a = 0;
		b = 0;
	}
	_test(int n1) {
		a = n1;
		b = 0;
	}
	_test(int n1, int n2) {
		a = n1;
		b = n2;
	}
public:
	int a;
	int b;
	int c;
};

int _main() {
	_test a;
	cout << "a.a : " << a.a << " a.b : " << a.b << endl;
	_test c(3, 4);
	cout << "c.a : " << c.a << " c.b : " << c.b << endl;
	_test d(a);
	cout << "d.a : " << d.a << " d.b : " << d.b << endl;

	return 0;
}